The two streams meet at a confluence. It takes many tributary streams to form a river. A river grows larger as it collects water from more tributaries. Streams usually form rivers in the higher elevations of mountains and hills. The areas of depression between hills or mountains are known as valleys.
The world's fastest production single piston engine aircraft produced in Great Britain, deployed from 1945 to 1953. Heavily Modified Sea Fury aircraft can be seen today as air racers. Heinkel He-162 562 mph. Arguably the fastest WW II jet fighter.
Gulfstream G650. Another aircraft from Gulfstream Aerospace, this is the fastest private chartered jet, which has a capacity for around 18 passengers. It is a twin-engine long range jet with a maximum speed of 610 mph. The plane is boosted by a couple of Rolls Royce BR 725 and two cockpit avionics by Honeywell Planeview.